[PATCH 4/4] usb: typec: mux: add TS5USBA224 driver

["Alvin Šipraga" <alvin@pqrs.dk>]

From: Alvin Šipraga <alsi@bang-olufsen.dk>

The TS5USBA224 USB High Speed/Audio switch mux is typically used
together with a Type-C port controller such as the TUSB320LAI. Below is
a simplified typical application on an embedded platform:

 ┌─────────────────────┐                      ┌───────────────────┐
 │                     │          I2C         │                   │
 │                     ├──────────────────────┤ I2C               │
 │      TUSB320LAI     │         INT_N        │                   │
 │                     ├──────────────────────┤     System-on-    │
 │                     │                      │             Chip  │
 │ CC1 CC2             │           ┌──────────┤ GPIO              │
 └──┬───┬──────────────┘           │          │                   │
    │   │                          │          │       USBOTG      │
    │   │                          │          │    VBUS   D+  D-  │
    │   │                          │          └──────┬─────┬───┬──┘
    │   │   ┌──────────────────────│─────────────────┘     │   │
    │   │   │          ┌───────────┴──┐                    │   │
    │   │   │          │        A_SEL │                    │   │
    │   │   │          │              │                    │   │
    │   │   │          │           D+ ├────────────────────┘   │
    │   │   │          │              │                        │
    │   │   │   ┌──────┤ D+/L      D- ├────────────────────────┘
    │   │   │   │      │              │
    │   │   │   │   ┌──┤ D-/R         │                   Line_L
    │   │   │   │   │  │            L ├─────────────────────────
    ┴   ┴   ┴   ┴   ┴  │              │                   Line_R
     USB Type-C port   │            R ├─────────────────────────
                       │              │
                       │  TS5USBA224  │
                       └──────────────┘

This driver controls the TS5USBA224 via the A_SEL pin. In addition, it
registers itself as a Type-C mux device. In the above scenario, the
driver may be notified via the port controller driver if the CC pins
indicate that an Audio Accessory is connected or not.

Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
---
 drivers/usb/typec/mux/Kconfig      |  10 +++
 drivers/usb/typec/mux/Makefile     |   1 +
 drivers/usb/typec/mux/ts5usba224.c | 102 +++++++++++++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 drivers/usb/typec/mux/ts5usba224.c

diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index edead555835e..82c25b117652 100644
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -19,4 +19,14 @@ config TYPEC_MUX_INTEL_PMC
 	  control the USB role switch and also the multiplexer/demultiplexer
 	  switches used with USB Type-C Alternate Modes.
 
+config TYPEC_MUX_TS5USBA224
+	tristate "TI TS5USBA224 USB High Speed/Audio switch mux driver"
+	select GPIOLIB
+	help
+	  Say Y or M if your system has a TI TS5USBA224 USB High Speed/Audio
+	  switch mux controller paired with a USB Type-C port controller.
+
+	  If you choose to build this driver as a dynamically linked module, the
+	  module will be called ts5usba224.ko.
+
 endmenu
diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
index 280a6f553115..4b5f318656a0 100644
--- a/drivers/usb/typec/mux/Makefile
+++ b/drivers/usb/typec/mux/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
 obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
+obj-$(CONFIG_TYPEC_MUX_TS5USBA224)	+= ts5usba224.o
diff --git a/drivers/usb/typec/mux/ts5usba224.c b/drivers/usb/typec/mux/ts5usba224.c
new file mode 100644
index 000000000000..4935dc8a0725
--- /dev/null
+++ b/drivers/usb/typec/mux/ts5usba224.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * TI TS5USBA224 USB 2.0/audio switch mux driver
+ *
+ * Copyright (c) 2021 Alvin Šipraga <alsi@bang-olufsen.dk>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/usb/typec_altmode.h>
+#include <linux/usb/typec_mux.h>
+
+struct ts5usba224 {
+	struct device *dev;
+	struct typec_mux *mux;
+	struct gpio_desc *a_sel;
+};
+
+static int ts5usba224_mux_set(struct typec_mux *mux,
+			      struct typec_mux_state *state)
+{
+	struct ts5usba224 *chip = typec_mux_get_drvdata(mux);
+
+	switch (state->mode) {
+	case TYPEC_MODE_AUDIO:
+		gpiod_set_value_cansleep(chip->a_sel, 1);
+		dev_dbg(chip->dev, "audio switch enabled\n");
+		break;
+	case TYPEC_STATE_USB:
+	case TYPEC_MODE_USB2:
+	default:
+		dev_dbg(chip->dev, "audio switch disabled\n");
+		gpiod_set_value_cansleep(chip->a_sel, 0);
+		break;
+	}
+
+	return 0;
+}
+
+static int ts5usba224_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct typec_mux_desc mux_desc = {};
+	struct ts5usba224 *chip;
+	int ret;
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->dev = dev;
+
+	chip->a_sel = devm_gpiod_get(dev, "asel", GPIOD_OUT_LOW);
+	if (IS_ERR(chip->a_sel)) {
+		ret = PTR_ERR(chip->a_sel);
+		return dev_err_probe(dev, ret, "failed to get A_SEL GPIO\n");
+	}
+
+	mux_desc.drvdata = chip;
+	mux_desc.fwnode = dev->fwnode;
+	mux_desc.set = ts5usba224_mux_set;
+
+	chip->mux = typec_mux_register(dev, &mux_desc);
+	if (IS_ERR(chip->mux))
+		return PTR_ERR(chip->mux);
+
+	platform_set_drvdata(pdev, chip);
+
+	return 0;
+}
+
+static int ts5usba224_remove(struct platform_device *pdev)
+{
+	struct ts5usba224 *chip = platform_get_drvdata(pdev);
+
+	typec_mux_unregister(chip->mux);
+
+	return 0;
+}
+
+static const struct of_device_id ts5usba224_of_match[] = {
+	{ .compatible = "ti,ts5usba224", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ts5usba224_of_match);
+
+static struct platform_driver ts5usba224_driver = {
+	.driver = {
+		.name = "ts5usba224",
+		.of_match_table = of_match_ptr(ts5usba224_of_match),
+	},
+	.probe  = ts5usba224_probe,
+	.remove = ts5usba224_remove,
+};
+
+module_platform_driver(ts5usba224_driver);
+
+MODULE_AUTHOR("Alvin Šipraga <alsi@bang-olufsen.dk>");
+MODULE_DESCRIPTION("TI TS5USBA224 mux driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1